If you just wanna finish the challenges, you don’t need so many items. Except for last stages, especially now, when Proteus cannot be used. The bosses have very strong slash attacks and would be wise to bring axes or bombs. Mana potions in 2 slots. Very important when the board doesn’t help you. And at legendary, the most important is to bring time stop. If you let the bosses fire, you have little chance to finish. Little John is very effective this event.
You may have a look at this thread. Like I already said in there, I did wrong. Should brought axes, not antidotes.